Hi Guys,

Need some help, i have a 2000 S500 with 10000 miles and check engine light cameon for afew days.My mechanic scanned it on his OBD reader and the code read random misfires, he told me to change the plugs as they are the original ones does this sound right. Has anyone had similar problems what did you do to fix it.
Any advice appreciated.
Thanks.[/align]

 

Hi,
Misfire illuminates the Check Engine Light.

Your car has only done 10k miles. Plugs SHOULD be good for 75k. I would have expected a cy;inder specific code if it was a PLUG. Unlikely all go down together.
However they COULD be the cause but so could a lot of other things. Plug leads securely fitted onto plugs. Leads clean? Was it wet at the time the CEL came on?

Since CEL went off on its own I suggest you run the car till you get a repeat.
MAYBE you had a bad tank of gas. Unlikely but possible.

Did the garage clear the fault code otherwise if the problem reappears it may mislead. Only random misfire. Not specific to a given cylinder?

I would stick with your existing plugs till there is a little more evidence they are the cause. (IMHO OE plugs are also likely better than many after market parts)

Lets see what happens.

 

Thanks for the info, but my plugs actually have 100k miles, i'll see if cel comes on again and take i back to be scanned for codes.

 

I had the same thing happen to me the other day. I was at a stop light and the engine bucked a bit and started misfiring. The mechanic later told me the same thing, that a few cylinders had misfired and that I should replace the plugs and the ignition harness. He said that it should be changed at the 100k mile service. but since I only had 85k I resisted.

I then realized that I must have had bad fuel, and I filled the tank with high test from a gas station I like, and it has been running fine since then.

Check that you have clean high test. Maybe your injectors got a bit dirty?

Papadelta

 

I had the same thing happen to me the other day. I was at a stop light and the engine bucked a bit and started misfiring. The mechanic later told me the same thing, that a few cylinders had misfired and that I should replace the plugs and the ignition harness. He said that it should be changed at the 100k mile service. but since I only had 85k I resisted.

I then realized that I must have had bad fuel, and I filled the tank with high test from a gas station I like, and it has been running fine since then.

Check that you have clean high test. Maybe your injectors got a bit dirty?

Papadelta

 

well i got 01 s430 with 78K my check engine light is on now...I went to SPEEDWAY GAS STATION(same like CITGO) Got BEST fuel PREMIUM and next day my check engine light was ON...I dont know,but now i will be going ONLY TO SHELL,BP and MOBIL

 

Maybe nothing to do with Brand of gas.
Get codes read ASAP.
At 78k quite likely its the MAF but without the codes I'm guessing.

 

I'm having the same issue with my 2000 S500 (mileage about 70k). The "check engine" light goes on for a few days, then goes off for a day or so. The car itself runs and performs great, regardless of whether the light is on. I got the codes read at a local Auto Zone and they were 0170 and 0173 (to my best recollection). The print out provided indicated that if both of these codes were set at the same time, to suspect a problem with the mass air flow (MAF) sensor. Given that the light goes on and off, should I rush to have this issue fixed? Also, if I do get this fixed, should I pay extra for the dealer's MAF sensor ($450 - Bosch brand I believe), or is theAuto Zoneversion ($286 - Cardone brand) sufficient? Any input will be greatly appreciated!

 

P0170/3 is indeed indicative of the MAF.
70k miles is also the usual problem pointB
The light is intermittent because you are on the limit of the threshold set within software. I suspect that you are also a "gentle" driver. become a little more aggressive and I bet the light will come on and stay on.
You will no doubt shortly find that the light comes on and stay on.
NO NEED TO RUSH OUT AND GET THE PROBLEM FIXED IMMEDIATELY. AS YOU STATE THE PROBLEM IS NOT ALWAYS NOTICEABLE TO THE DRIVER, (Sorry about caps)
Sometimes a MAF can be cleaned with proprietary carburettor cleaner, othertime a new unit is required. I strongly recommend using a genuine MB part although some people state that non MB parts work fine. My advice is play safe.

 

Thank you snanceski. You are absolutely correct that I don't drive the car agressively. Playing it safe with the MB part also sounds prudent. Do you know what I should expect in terms of labor time to replace the MAF? If I understand correctly, it's located at the rear of the engine just under the engine cover. If that is the case, I'd expect 1 hour max.Does this sound reasonable? (I assume from reading your posts that you may be a MB technician.) Thanks again.